1. Field of the Invention
The present invention relates to an organic thin film transistor and a flat panel display device using the same, and more particularly, to an organic thin film transistor formed between source and drain electrodes and an organic semiconductor and a flat panel display device using the same.
2. Discussion of Related Art
When fabricating an organic semiconductor device, an energy barrier between an organic semiconductor and a metal should be removed by forming an ohmic contact between the organic semiconductor and the metal. In a conventional organic semiconductor device, pentacene, and poly-3-hexylthiophene, fluorene-bithiophene are used as a p-type organic semiconductor, and lutetium bisphthalocyanine, thulium bisphthalocyanine, tetracyanoquinodimethane (TCVQ), C60, C70, 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA), 1,4,5,8-naphthanlene tetracarboxylic diimide (NTCDI), 11,11,12,12-tetracyanonaphtho-2,6-quinodimethane (TCNNQ), NTCDI-C8H, NTCDI-C12H, NTCDI-C18H, NTCDI-BnCF3, and NTCDI-C8F are used as an N-type organic semiconductor.
Since the organic transistor materials have high work functions ranging from 5.1 eV to 5.5 eV, the ohmic contact is formed using gold (Au) satisfying the high work functions or surface-treated indium-tin oxide (ITO). However, since a shadow mask type patterning is required when using gold as the ohmic contact, gaps between channels are limited by the mask edges; and, when ITO is used as the ohmic contact, the lifespan and the stability of the device deteriorate.